In-line fluid flow static mixers are known in the art and generally consist of mixing baffles arranged so that when a material is discharged from one baffle, it discharges with a swirling action and strikes the downstream baffle. The fluid flow divides before it passes on to the next succeeding baffle, which again divides the flow into various streams. While this type of mixer has achieved commercial success for mixing, use of a static mixer is ineffective with many high viscosity fluids. U.S. Pat. Nos. 4,511,258 and 4,936,689 disclose static mixer having a sinuous cross-section with each section being axially staggered with respect to another section, however, no teaching is made on presenting such a mixer to highly viscous materials.
In addition, such mixers would be economically unfeasible in situations wherein a high flow rate and rapid mixing is required.
Hydrodynamic cavitation is the result of a flow constriction wherein a liquid falls below the vapor pressure and forms vapor-filled gas bubbles. If the static pressure then increases and exceeds the vapor pressure, these vapor-filled gas bubbles collapse implosively. Cavitation and the associated effects are also known to be useful in mixing, emulsifying and dispersing various components in a flowing liquid. The mixing action is based on a large number of forces originating from the collapsing or implosion of cavitation bubbles. If during the process of movement of the fluid the pressure at some point decreases to a magnitude under which the fluid reaches a boiling point for this pressure, then a great number of vapor-filled cavities and bubbles are formed. Insofar as the vapor-filled bubbles and cavities move together with the fluid flow, these bubbles and cavities may move into an elevated pressure zone. Where these bubbles and cavities enter a zone having increased pressure, vapor condensation takes place within the cavities and bubbles, almost instantaneously, causing the cavities and bubbles to collapse, creating very large pressure impulses. The magnitude of the pressure impulses within the collapsing cavities and bubbles may reach ultra high pressures implosions leading to the formation of shock waves that emanate from the point of each collapsed bubble.
Hydrodynamic cavitation typically takes place by the flow of a liquid under controlled conditions through various geometries. The phenomenon consists in the formation of hollow spaces which are filled with a vapor gas mixture in the interior of a fast-flowing liquid flow or at peripheral regions of a fixed body which is difficult for the fluid to flow around and the result is a local pressure drop caused by the liquid movement. At a particular velocity the pressure may fall below the vapor pressure of the liquid being pumped, thus causing partial vaporization of the cavitating fluid. With the reduction of pressure there is liberation of the gases which are dissolved in the cavitating liquid. These gas bubbles also oscillate and the give rise to the pressure and temperature pulses.
It is known that devices exist in the art which utilize the passage of a hydrodynamic flow through a cylindrical flow-through chamber having a series of baffles confronting the direction of hydrodynamic flow to produce varied cavitation effects. The baffles provide a local contraction of the flow as the fluid flow confronts the baffle element thus increasing the fluid flow pressure. As the fluid flow passes the baffle, the fluid flow enters a zone of decreased pressure downstream of the baffle element thereby creating a hydrodynamic cavitation field. U.S. Pat. No. 5,492,654 discloses a cylindrical flow-through chamber having internally disposed baffles. In this disclosure the upstream baffle elements have a larger diameter than the downstream baffle elements. Such a device is utilized in an attempt to create and control hydrodynamic cavitation in fluids wherein the position of the baffle elements is variable.
Although the hydrodynamic cavitation devices exist in the prior art, there is nevertheless a need for improvement in many respects to provide a fluid shearing effect that allows for the mixing of fluids from multiple sources.